save DHCP leases on data disk

closes #4

terraform/data/main.tf

@@ -0,0 +1,30 @@
+terraform {
+  backend "pg" {
+    schema_name = "hermes-data"
+    conn_str    = "postgres://terraform@10.42.0.1/terraform_state"
+  }
+
+  required_providers {
+    libvirt = {
+      source = "dmacvicar/libvirt"
+    }
+  }
+}
+
+provider "libvirt" {
+  uri = "qemu+ssh://root@atlas.lan/system"
+}
+
+resource "libvirt_volume" "data" {
+  name = "hermes-data"
+  pool = "data"
+  size = 1024 * 1024
+
+  lifecycle {
+    prevent_destroy = true
+  }
+}
+
+output "data_disk_id" {
+  value = libvirt_volume.data.id
+}